Locking toggle arrangement for a capstan



March 17, 1970 A. UTERMGHLE 3,501,130

LOCKING TOGGLE ARRANGEMENT FOR A CAPSTAN Filed March 14, 1968 INVENTOR 4001/ 0722/4019! E ATTORNEY United States Patent 3,501,130 LOCKING TOGGLE ARRANGEMENT FOR A CAPSTAN Adolf Utermiihle, Bremerhaven, Germany, assignor to Aktiengesellschaft Weser, Bremen, Germany Filed Mar. 14, 1968, Ser. No. 713,078 Claims priority, application Germany, Mar. 17, 1967,

Int. Cl. B66d 1/330; F16d 53/00 US. Cl. 254150 9 Claims ABSTRACT OF THE DISCLOSURE A capstan which is to be turned under load in one direction about its axis includes an annulus of the teeth coaxial with the axis of rotation of the capstan. A locking pawl is provided in form of a toggle lever pivotally mounted in such a manner that in a first position of the two lever sections with reference to one another, in which they are slightly out of alignment with each other, a free end of the toggle lever engages one of the gear teeth and prevents turning the capstan end in the one direction, the reaction force provided by the load acting on the free end of the toggle lever tending to move the same from the first position to a collapsed position. A releasable blocking arrangement engages one portion of the toggle lever and is movable between a blocking position in which it prevents the collapse of the toggle lever and a releasing position in which it permits such collapse.

BACKGROUND OF THE INVENTION The present invention relates to capstans in general, and more particularly to capstans provided with locking pawl means. More particularly the present invention re lates to so-called warping drums of the type which is used on ships, in harbors and in other installations wherever it is necessary to maintain a rope or tow placed about the capstan in tightened condition when the capstan is at rest, that is when it is not rotated in a sense effecting takeup of the rope.

It is of course known to provide capstans for this purpose wherein the drum carries a disc or an annulus of gear teeth, that is a ratchet gear, into which the free end of a pivotally mounted blocking pawl engages. Usually, biasing means is provided which urges the blocking pawl to a position in which it engages the ratchet and prevents rotation of the capstan in a direction permitting unwinding of the rope but which permits rotation of the capstan in opposite direction in which the rope can be further tightened if desired. However, in such arrangements it is necessary, whenever the locking pawl is to be released to permit the rotation of the capstan in the direction unhinding of the rope, to initially effect momentary turning of the capstan in opposite direction so as to free the engaged end of the locking pawl. Under certain circumstances this is highly undesirable because the time therefor, brief as it may be, is not all available. For instance, in case of emergency where the release of the capstan in a sense permitting unwinding of the rope must be almost instantaneous such as in the case of capsizing of a ship which is being towed, the necessary time is usually not available with the result that with these aforementioned prior-art constructions it is necessary in these circumstances to .sever the rope or tow.

It is therefore a general object of the invention to provide a capstan which is not subject to this disadvantage.

More particularly it is an object of the present invention to provide such a capstan wherein the locking pawl preventing rotation of the capstan in a sense permitting unwinding of the rope is capable of immediate release 3,501,130 Patented Mar. 17, 1970 without necessitating the capstan in opposite directions to counter the load or torque acting thereupon.

An additional object of the present invention is to provide such a capstan wherein it is the load or torque acting upon the capstan which itself assists in the release of the locking pawl.

SUMMARY OF THE INVENTION In accordance with one feature of my invention I provide, in a capstan which is to be turned under load in one direction about its axis, at least one abuttment member fixed to such said capstan and having a substantially radially extending abuttment face. Locking pawl means is provided in form of a toggle lever having a pair of lever portions pivotally connected at adjacent ends thereof. One of these lever portions is pivotally connected at the other end thereof to a fixed part and the other lever portion engages with the free end the abutment phase of the abutment member so as to lock the capstan against rotation in the one direction while the lever portions are in a first position in which they are slightly out of alignment with each other. The reaction force provided by the load and acting on the free end of the aforementioned other lever portion tends to move the toggle lever from the first position thereof to a collapsed second position. Releasable blocking means engages one of the lever portions and is movable between a blocking position in which it prevents the toggle lever from moving to the collapsed position, and a releasing position in which it permits the movement of the toggle lever to such a collapsed position under the influence of the load acting upon the capstan and therefore upon the free end of the aforemmentioned other lever portion.

With a construction according to my invention, the reaction force of the load exerted upon the capstan by the rope convoluted thereabout, which force is usually very high and may be on the order of tons or more, not only will not counteract release of the locking pawl from its locking position, but will actually facilitate and initiate such release as soon as the locking pawl in form of a toggle lever has been freed for its collapsing movement. Thus, the collapse of the toggle lever and thereby the disengagement of the locking pawl from the ratchet associated with the capstan is initiated and effected by the reaction force acting upon the capstan.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additoinal objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side-elevational view in somewhat diagrammatic form of a device embodying my invention;

FIG. 2 is a top-plan view of the device shown in FIG. 1, illustrating it in a position in which the capstan has blocked against rotation under the influence of a load acting on the capstan; and

FIG. 3 is a view similar to FIG. 2, but showing the device or the locking pawl released so that the capstan can rotate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing in detail, in FIGS. 1 and 2 thereof, it will be seen that the capstan comprises a drum or a drum head 1 which at its underside is rigid with a ratchet wheel or disc 2. This is conventional and need not be pointed out that the ratchet wheel must of course have the teeth which are illustrated in the drawing. A supporting plate 3 is provided on which there is mounted a locking pawl means in form of a toggle lever 4. The toggle lever 4 consists of two sections 4a and 4b. The section 4a is mounted on the support 3 at its free end for turning movement about the pivot 5. The section 412 is mounted on the section 4a for pivotal movement about the pivot 6. The two sections 4a and 4b together thus constitute a toggle lever 4 and the free end of the section 4b is adapted to engage the teeth of the ratchet disc 2.

In the locking position illustrated in FIG. 2 the two sections 4a and 4b together are located in a position in which they are slightly out of alignment with each other and in which the free end of the section 4b engages one of the teeth of the ratchet disc 2. It is of course assumed that a tow or rope is wound onto the drum head 1 and exerts a pull tending to rotate the drum head 1, and thereby the ratchet disc 2 associated therewith, in the direction indicated by the arrow shown in FIG. 2. Such rotation is prevented by the engagement of the free end of the section 417 as shown in FIG. 2.

However, the reaction force provided by this pull or load which tends to rotate the capstan in the direction indicated by the arrow in FIG. 2 will also tend to collapse the toggle lever 4, that is to pivot the section 4b about the pivot 6 and at the same time to pivot the section 4a about the pivot to the position illustrated in FIG. 3. In this position the toggle lever 4 no longer engages the teeth of the ratchet disc 2 and the capstan is free to turn in the direction indicated by the arrow, thereby permitting unwinding of the rope or tow wound on to the drum head 1. This release, that is this movement of the toggle lever 4 to collapse position as shown in FIG. 3, will auto matically take place when a force acts upon the capstan in a sense tending to rotate the drum head 1 and the ratchet disc 2 in the direction of the arrow, unless the collapse of the toggle lever 4 is counteracted.

For this purpose I have provided a blocking lever 7 having a longer and a shorter arm which together define an angle. I have found it advantageous if this angle is smaller than 90. The shorter arm of the lever 7, which matter is pivotable about the pivot point 8. Pivot point 8, is the one which is directed towards the toggle lever 4 which it engages, as clearly shown in FIG. 2, when the toggle lever is to be in the first position in which it prevents rotation of the capstan. The pivot axis defined by the pivot point 8 is located approximately at the apex of the angle defined between the two arms of the lever 7 and it will be appreciated that the central longitudinal axis of the shorter arm of the lever 7 is so arranged, as shown in the drawing, that it is inclinedto the longer arm and with reference to an imaginary vertical intersecting the pivot axis 8 and the toggle lever 4. The blocking lever 7 is provided, of course, for the purpose of counteracting the forces exerted by the capstan under load which tend to collapse the toggle lever so that these forces are incapable of displacing the sections 4a and 4b of the toggle lever to a position where the collapse can take place. The longer arm of the blocking lever 7 is engaged in the region of its free end by a hook member 9 which is mounted for pivotal movement about a pivot point 9a and which is associated with a linkage arrangement 10 which in turn is connected with an actuating lever 11. The actuating lever may be either gripped by hand or may, for instance, be connected with a rope 12 or a similar expedient so that, when the actuating lever 11 is manipulated, the hook 9 will be pivoted about the pivot point 9a to a position where it will disengage the free end of the longer arm of the lever 7, that is out of the position which is illustrated in FIG. 2. When this takes place the blocking lever 7 will no longer be able to assist the collapsing force acting upon the toggle lever 4 and will be pivoted about the pivot point 8 as the toggle lever 4 collapses to the position illustrated in FIG. 3.

I have found it advantageous and in the interest of a compact efficient construction to mount the components of the locking arrangement, that is all the components illustrated in FIG. 2 with the exception of the drum head 1 and the ratchet disc 2, on a common support plate 3 which has already been identified before. On this support plate 3 there are provided guide elements 13 which need not be further discussed, but which serve to guide the various components identified herebefore for movement between their different positions. A stop is provided against which the toggle lever 4 abuts when it is in the first or locking position thereof, that is the position illustrated in FIG. 2. A biasing means, here identified as a biasing spring 15, serves to normally deflect the sections 4a and 4b of the toggle lever 4 to their first or locking position illustrated in FIG. 2. However, the force of the biasing spring 15 is of course not sufficient to overcome the reaction force provided by the torque acting upon the capstan so that, when the blocking lever 7 is released by arresting arrangement therefore, the spring 15 will yield and permit collapse of the toggle lever 4.

With the arrangement according to my invention a substantially instantaneous release of the capstan for rotation in the direction in which the torque is exerted thereon is possible even if the pull exerted by the rope element wound upon the drum head 1 is extremely great, so that reliable release is guaranteed at all times.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a capstan arrangement, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In a capstan which is to be turned under load in one direction about its axis, at least one abutment member fixed to said capstan and having a substantially radially extending abutment face; locking pawl means in form of a toggle lever having a pair of lever portions pivotally connected at arjacent ends, one of said lever portions being pivotaly connected at the other end thereof to a fixed part and the other lever portion engaging with its free end said abutment face for locking said capstan against rotation while said lever portions are in a first position slightly out of alignment with each other, and the reaction force provided by said load on said free end of said other lever portion tending to move said toggle lever from said first position to a collapsed second position; and releasable blocking means engaging one of said lever portions and movable between a blocking position preventing said toggle lever from moving to said collapsed position and a releasing position permitting movement of said toggle lever to said collapsed position under the influence of said load, said releasable blocking means comprising a blocking lever mounted for turning movement between said blocking position and said release position and having a first and a second section engaging said one lever portion when said blocking lever is in said blocking position, and movable connecting means adapted to engage said first section for preventing said blocking lever from moving to said releasing position.

2. In a capstan as defined in claim 1, wherein said first section of said blocking lever is longer than said second section and defines an angle with the same.

3. In a capstan as defined in claim 2, wherein said angle is smaller than 90.

4. In a capstan as defined in claim 1, wherein said first section has a terminal end, and wherein said arresting means includes a pivotally mounted hook member adapted for pivotal movement to and from an engaging position in which it engages said terminal end of said first section for thereby preventing said blocking lever from moving to said releasing position thereof.

5. In a capstan as defined in claim 4; said arresting means further comprising an actuating member, and a linkage arrangement operatively connecting said actuating member with said hook member for effecting pivotal movement of the same from said engaging position in response to manipulation of said actuating member.

6. In a capstan as defined in claim 1; and further comprising support means common to said locking pawl means, said blocking lever and said arresting means.

7. In a capstan as defined in claim 6; and further comprising guide elements operatively associated with said locking pawl means, said blocking lever and said arresting means for guiding the same during movement thereof.

8. In a capstan as defined in claim 1; and further comprising 'biasing means associated at least with said locking pawl means and operative for biasing the same to said first position thereof.

9. In a capstan as defined in claim 1; and further comprising biasing means associated with the respective means and operative for biasing said locking pawl means to said first position, said blocking lever to said blocking position, and said arresting means into engagement with said first section of said blocking lever.

References Cited UNITED STATES PATENTS 3,033,531 5/1962. Patterson 188 82.7

HARVEY C. HORNSBY, Primary Examiner US. Cl. X.R. 

